Maybe every 5-10 minutes, one of my skills stop going off when I push the buttons, both on the mouse and keyboard. I have to remove the skill, then re-add it, and it starts working again.
I am having this happen to the attack I have on my right mouse button.
If you have an empty skill slot, putting the skill in two spots seems to fix the issue.
I have the same issue with Umbral Blades on right mouse not working after playing for a bit.
Removing and reassigning the skill fixes it temporily
Same issue - bug report filed.